Method for processing a fluid and fluid processing device

ABSTRACT

The present invention relates to improved methods for processing fluids and to a fluid processing device ( 1 ) for use in a centrifuge comprising: (a) a first holder ( 14 ) form-fit to the shape of a first tube ( 18 ) for holding said first tube ( 18 ) whereby said first tube ( 18 ) has a first cross section (A1); and (b) a second holder ( 22 ) form-fit to the shape of a second tube ( 26 ) for holding said second tube ( 26 ) whereby said second tube ( 26 ) has a second cross section (A2) that is different from said first cross section (A1). With the fluid processing devices and the methods according to the invention, it is possible to simplify the centrifugal processing steps for a given fluid processing sequence and to automate them.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a divisional of U.S. Ser. No. 11/992,616, filed Sep.15, 2009, which is a National Stage filing under 35 U.S.C. §371 ofInternational Application No. PCT/EP2006/066759, filed Sep. 26, 2006,which claims priority to European Application No. 05020948.5, filed Sep.26, 2005, the contents of which are incorporated herein by reference intheir entireties.

BACKGROUND OF THE INVENTION Field of the Invention

The present invention relates to a fluid processing device and a methodfor processing a fluid. In particular, the present invention relates toa device and a method for preparing biomolecules including but notlimited to nucleic acids, proteins, peptides, polypeptides, nucleotides,and lipids.

In many technical fields, like chemistry, biology, medicine orenvironmental protection, fluids have to be analyzed, processed, orbrought into reaction with each other. For this purpose, fluids arefiltered, cooled, heated, decomposed, washed, pipetted, or treated byother procedures. Often, in order to prepare a fluid, it is necessary togo through a long sequence of fluid processing steps. Further, in manycases, large sets of different fluids need to be processed according tothe same sequence or batches of the same fluid need to be processed inparallel. This may be time consuming, limit the throughput and be proneto errors occurring during the procedure.

Fluid processing is used, for example, in the field of extracting and/orpurifying biomolecules like nucleic acids or proteins. For example, awidely known method of purifying biomolecules is based on the steps ofgenerating access to the content of a biological sample (“lysis”),selective binding of components of the content of the biological sampleto a solid support or carrier material (“binding”), removing unwantedcomponents from the solid support or carrier material (“washing”), andeluting the component of interest (“elution”).

In order to allow for a selective adsorbing and desorbing in the processof biomolecules purification, filter elements made of, e.g., silica-gelhave been developed that on the one hand are porous or matrix-like inorder to allow a fluid to pass through the filter element, and that onthe other hand have a surface to which the biomolecules bind in aspecific or nonspecific process. In other purification proceduresbiomolecules are detained on filter elements simply by the principle ofsize exclusion. In either way, if a biomolecule, e.g. a nucleic acidcontaining fluid passes through the filter element, some or all of thecontent remains with the filter element while the rest passes throughthe filter element.

Further, in order to recover the biomolecule from the filter element, anelution fluid, e.g. nuclease-free water, is dispensed onto the filterelement for desorbing the biomolecule. This way, the biomolecule ofinterest is eluted from the filter element to be collected in acollection tube. Such filter elements are often applied as membraneseither implemented in single tubes having an inlet opening and an outletopening, or in multiwell plates, and processed using centrifuges (“spinformat”) or vacuum based apparatuses. Single tubes with an inlet openingand an outlet opening that have a membrane and that can be spun in acentrifuge are also known as columns, spin columns, or single spincolumns.

In general, the advantages of centrifuge based procedures over vacuumbased methods are higher purity, higher concentration and a lowerpotential of cross contamination. In general, the best results for thepurification of biomolecules, with regard to quality and concentrationcan be achieved using single spin columns combined with high g forces(>10.000×g) as there is a minimum of cross contamination and a maximumrecovery from the membrane. A drawback is the labor intensive manualhandling of spin columns increasing the error proneness and the processtime if different samples are to be treated or processed simultaneously.A higher degree of standardization and automation as well as a higherthroughput can be achieved by using multiwell plate formats mostly atthe cost of quality and/or quantity.

QIAGEN offers a wide range of purification protocols for differentbiomolecules from a variety of biological samples all based on theoverall Bind-Wash-Elute principle by using different filter materialsand devices as, for example, described in WO 03/040364 or U.S. Pat. No.6,277,648. The commercially available product “QIAGEN QIAprep SpinMiniprep Kit” for example discloses a typical purification sequence andoffers standardized QIAprep Spin columns and 2 ml collection tubes foruse in a centrifuge, and several reagents and buffers.

There are several publications relating to the automated processing offluids involving centrifugal steps. U.S. Pat. No. 4,344,768 describes apipettor apparatus for automatically transferring accurate and precisemultiple quantities of samples (e.g., blood serum) and reagent to therotatable transfer disc of a centrifugal analyzer. EP 0 122 772describes a chemical manipulator adapted to automate the analysis ofliquids of a μl unit, such as a DNA sample. U.S. Pat. No. 6,060,022describes an automated sample processing system including an automaticcentrifuge device. GB 535,188 describes an apparatus for obtaining aplurality of working bucket angles at a given speed of rotation of acentrifuge.

U.S. Pat. No. 5,166,889 describes a sampling system adapted for blood,wherein a plurality of sample tubes are positioned for ready access on asupport wheel, EP 569 115 A3 describes a centrifuge-based device forpreparing DNA, and U.S. Pat. No. 539,339 describes an integralbiomolecule preparation device using a centrifuge.

Several apparatuses for the preparation of samples using centrifugationare commercially available. “GENTRA Autopure LS” (GENTRA) and“AutoGenflex 3000” (AutoGen) are automated systems with an integratedcentrifuge for the isolation of e.g. DNA after precipitation withoutusing filtration elements. “DNA-Spinner” (PerkinElmer), “Genesis FE 500”(Tecan) and Microlab STARplus (Hamilton) are examples for more opensystems where a liquid handling instrument is combined with an automatedcentrifuge for the use of multiwell plates.

On the other hand, for example, the “BioRobot 3000/8000” (QIAGEN) can beused for the preparation of samples, e.g. nucleic acids, in a 96-wellformat using vacuum filtration whereas the “Fuji QuickGene 800” appliesa low pressure filtration principle on single columns.

However, most existing integrated systems for an automated preparationof biomolecules from fluids applying centrifugation are designed for apreparation of only specific procedures. Other instrument setupscomprising an automated centrifuge are optimized for high throughputpreparations using multiwell filtration plates. A drawback of existingautomation systems is their inability to process high qualitypreparation procedures based on spin-columns without manualinterventions.

SUMMARY OF THE INVENTION

In order to overcome one or several of the above mentioned problems, andin order to improve known methods of processing fluids, fluid processingdevices according to the independent claims 1, 8, 14, 21, 27, and 35, arotor according to independent claim 74, and methods for processing afluid according to the independent claims 77 and 79 are provided.

Further aspects, improvements and variations of the invention aredisclosed in the dependent claims, the figures and the description.

With the fluid processing devices according to the claims 1, 8, 14, 21,27 and 35, and with the methods according to the claims 77 and 79, it ispossible to cany out a wide range of different preparation proceduresinvolving one or more tubes (e.g. spin columns, collection tubes etc.)within one and the same fluid processing device. In particular, it ispossible to provide for a fully automated and standardized preparationof a variety of biomolecules from fluids using well establishedprocedures and proven spin column based chemistry for low to mediumthroughput needs, preferably without any manual intervention. Forexample, the fluid processing device can be used for an automatedpreparation of biomolecules using filtration elements. It can further beused for an automated processing of the bind-wash-elute steps, orlysing-bind-wash-elute steps, for biomolecule extraction andpurification procedures in a single fluid processing device. Thisenables a one-to-one correspondence between a processed sample and afluid processing device. Thus, the risk of cross-contamination andmisallocation of samples can be minimized.

Further, the automated processes can be carried out with the fluidprocessing device used as a disposable device. Further, with the fluidprocessing device having a first holder and a second holder, the tubes(e.g. spin columns and collection tubes) can be uniquely assigned torespective positions on the fluid processing device so thatcross-contamination and likelihood of confusing the tubes can beminimized. At the same time, the fluid processing device according tothe invention provides a platform for a large variety of preparationsprocedures. It can further be used for automatically handle multipleindividual tubes or spin columns in parallel in order to reach highstandardization analogues to multiwell formats. Further, it is possibleto provide a device and a method for automated and standardizedpreparation of a variety of biomolecules from fluids using wellestablished procedures and proven spin column based chemistry for low tomedium throughput needs.

According to a first aspect of the invention, a fluid processing deviceis provided having a first holder for holding a first tube having afirst cross section, and a second holder for holding a second tubehaving a different second cross section. This may help to increasethroughput by centrifuging different types of tubes at a time in orderto carry out different fluid processing steps at a time. For example, ifthe first tube is a filter tube for filtering a fluid duringcentrifugation and the second tube is a collection tube for holding afluid during centrifugation, filtering and pelleting of different fluidsmay be carried out in only one centrifuging step.

Further, if the first tube and the second tube are geometrically adaptedto each other so that the first tube can be inserted into the secondtube, the fluid processing device can be prepared such that twodifferent processing steps within a centrifuge can be carried out in arow by transferring the first tube directly from the first holder to thesecond holder. This saves time, reduces error proneness and eliminatesthe risk of cross contamination compared to the case where before eachprocessing step in a centrifuge, the tubes need to be prepared outsidethe centrifuge and returned into the centrifuge. For example, byproviding the first holder with a first tube used for fluid filteringand the second holder with a second tube used for fluid collection, thechange from fluid filtering to fluid collection may be carried out bysimply transferring the first tube from the first holder to the secondtube held by the second holder.

In particular, with the first tube having a filter element for bindingbiomolecules, the first holder can be used for holding the first tube toperform a binding and one or several washing steps while, bytransferring the first tube from the first holder to the second holderholding a second tube, the second holder can be used for holding thesecond tube for collecting the purified biomolecules eluted from thefirst tube. This way, with the fluid processing device according to theinvention, binding, multiple washing and elution steps can be carriedout in a row within the centrifuge without having to move the first tubeout and back into the centrifuge for inserting the first tube into acollection tube. Thus, the risk of cross contamination due to splashesfrom droplets at the outlet of filter tubes during tube transfer stepsfrom and to the centrifuge can be eliminated.

Preferably, the fluid processing device comprises a first containerhaving a first container volume for holding a fluid whereby, preferably,the first holder is arranged with respect to the first container suchthat a fluid flowing through the first tube flows into the firstcontainer. With the first container, it is possible to collect thefluids that may have passed through the first tube to reduce crosscontamination with, e.g., samples of adjacent tubes within thecentrifuge. In particular, with a sufficiently large first containervolume, larger amounts of waste fluids originating from the binding stepand the washing step can be discarded iri the first containers. Thissaves additional time consuming waste disposal steps and reduces thenumber of unloading and reloading steps for unloading and reloading thecentrifuge. Further, while a large first container volume is generallydesired, it is generally preferred that the first container is arrangedwith respect to the first holder so that the dimension of the fluidprocessing device as a whole is sufficiently small to be also usable insmall centrifuges. It is further preferred that the first holder isarranged with respect to the first container in a way that a first tubeheld by the first holder does not come in contact with the fluid in thefirst container at any step of the process.

Further, according to one aspect of the present invention, the firstholder is form-fit to the shape of the first tube and the second holderis form-fit to the shape of the second tube to provide for a secureholding of the first tube with respect to the second tube duringcentrifugation of the fluid processing device.

According to a further aspect of the invention, the first container hasa first container volume that is different from a second containervolume into which a fluid flows that flows through the first tube heldby the second holder at a second position. This way, it is possible toprovide for a large first container volume for collecting large volumesof fluids that flow through the first tube during the binding andwashing steps while using only a small second container volume forcollecting the purified biomolecule during elution. By having thecontainer volumes adjusted to the actual needs of a given processingsequence, over-sizing of the equipment that needs to be centrifuged canbe avoided which in turn facilitates the use of smaller, less expensivecentrifuges.

According to a further aspect of the invention, a first container isprovided that has a container volume with a container cross section thatis at least ten percent larger than the first cross section of the firsttube. Preferably, the container cross section is taken in a planeparallel to the first cross section of the first tube when held by thefirst holder. By providing a larger container cross section compared tothe first cross section, the container volume for collecting the fluidsoriginating from the binding and washing steps may be enlarged

According to a further aspect of the invention, a first container havingan inner surface for defining a first container volume is providedwhereby the inner surface adjoins to the second holder. Having the innersurface of the first container extended up to the second holder helps tomaximize the first container volume for collecting the fluidsoriginating from the binding and washing steps. By adjoining the innersurface of the first container to the second holder, additionalstability of the fluid processing device, e.g., against a centrifugalforce, can be provided.

It is a further aspect of the present invention to provide for a holderhaving a first stopper for holding a first tube and thereby defining afirst stopper plane, and to provide for a second holder having a secondstopper for holding a second tube and thereby defining a second stopperplane whereby the second stopper plane is different from the firststopper plane. This way, it is possible to hold the first tube at aheight different from the height of the second tube as measured alongthe projections onto the respective tube axes. Holding the first and thesecond tubes at different heights facilitates easier access to the tubesif the holders are positioned closely with respect to each other. Itfurther provides the opportunity to discriminate between the two holdingpositions.

It is a further aspect of the present invention to provide for at leastone first cap fixture means for holding a first cap of a first tube in adefined position with respect to the first holder during centrifugation.Preferably, the first cap fixture means are arranged such that the firstcap is held at a position that leaves the first tube's inlet openingopen during centrifugation and makes it accessible to pipetting means.This way, the first tube can be centrifuged with an open inlet openingwithout having to worry about damage caused by the first tube's firstcap hanging loose during centrifugation. An advantage of an open inletopening of the first tube during centrifugation is that aftercentrifugation, fluids like, e.g., a wash fluid can be dispensed intothe tube without having to remove a cap from the inlet opening.

A further aspect of the present invention is a method including the stepof automatically transferring a first tube directly from a first holdingposition within a centrifuge to a second holding position within thecentrifuge. The direct transfer can be used to reduce the stepsnecessary for purifying biomolecules. It further eliminates errorscaused by mix up or misallocation of sample tubes during manual tubetransfer steps outside the centrifuge.

A further aspect of the present invention is a method including the stepof transferring a first tube from said holder of one of at least onefluid processing device to a second holder of one of said at least onefluid processing device. This way, binding, washing and elution of thebiomolecules can be carried out without having to load and unload thecentrifuge.

BRIEF DESCRIPTION OF THE DRAWINGS

The following figures below disclose several embodiments according tothe invention for illustrational purposes only. In particular, thedisclosure within the figures is not meant to limit the range ofprotection of the invention:

FIGS. 1A-1B: a first tube having an inlet opening and an outlet opening

FIGS. 1C-1E a second tube having an inlet opening that is sized toreceive the first tube;

FIGS. 2A-2E: A first fluid processing device according to the inventionfor holding a first tube and a second tube having different crosssections;

FIGS. 3A-3E: A second fluid processing device according to the inventionfor holding a first tube and a second tube having different crosssections whereby the fluid processing device has a first container;

FIGS. 4A-4E: A third fluid processing device according to the inventionfor holding a first tube whereby the fluid processing device has a firstcontainer and a second container of different size;

FIGS. 5A-5E: A fourth fluid processing device according to the inventionfor holding a first tube and a second tube having different crosssections whereby the fluid processing device has a first containerextending beyond the second holder in a projection normal to the firstaxis;

FIGS. 6A-6E: A fifth fluid processing device according to the inventionfor holding a first tube, a second tube and a third tube having at leasttwo different cross sections whereby the fluid processing device has afirst container;

FIGS. 7A-7B: A sixth fluid processing device according to the inventionfor holding a first tube, a second tube, a third tube and a fourth tubehaving different cross sections whereby the fluid processing device hasa first container,

FIGS. 8A-8B: A seventh fluid processing device according to theinvention for holding a first tube, a second tube, a third tube, afourth tube and a fifth tube having different cross sections whereby thefluid processing device has a first container;

FIGS. 9A-9B: An eighths fluid processing device according to theinvention for holding a first tube and a second tube having differentcross sections, the fluid processing device having a first container andhaving connection means;

FIGS. 10A-10B: A ninth fluid processing device according to theinvention for holding a first tube and a second tube having differentcross sections whereby the fluid processing device has a first containerextending beyond the second holder in a projection normal to the firstaxis and, further, having connection means;

FIGS. 11A-11B: A tenth fluid processing device according to theinvention for holding a first tube, a second tube and a third tubehaving different cross sections whereby the fluid processing device hasa first container and, further, connection means;

FIG. 12: An eleventh fluid processing device according to the inventionfor holding a first tube, a second tube and a third tube havingdifferent cross sections whereby the fluid processing device has a firstcontainer and connection means comprising a holding structure forremovably holding the first container;

FIG. 13: An twelfth fluid processing device according to the inventionthat is like the eleventh fluid processing device including first andsecond cap fixture means for holding first and second caps;

FIGS. 14A-14B: An thirteenth fluid processing device according to theinvention that is like the twelfth fluid processing device including twofirst cap fixture means and one second cap fixture means;

FIG. 15: A fourteenth fluid processing device according to the inventionhaving a first stopper and a second stopper defining different stopperplanes;

FIG. 16: A fifteenth fluid processing device according to the inventionhaving a first container as well as a first stopper and a second stopperdefining different stopper planes;

FIG. 17A: A top view of a rotor according to the invention connected totwelve fluid processing devices according to the invention;

FIG. 17B: A first cross sectional view through the rotor according tothe invention illustrating connection means interacting with the swingaxle receiver;

FIG. 17C: A second cross sectional view through the rotor according tothe invention illustrating the first and second swing prevention means;

FIG. 18A-18C: A perspective view on a fluid processing device accordingto the invention having first, second and third swing prevention means;

FIG. 19A Schematic illustration of a direct first transfer within acentrifuge in tangential direction

FIG. 19B Schematic illustration of a direct first tube transfer within acentrifuge in radial direction

FIG. 20A Schematic illustration of a first tube transfer in radialdirection from a first holder to a second holder within a fluidprocessing device according to the invention;

FIG. 20B Schematic illustration of a first tube transfer in tangentialdirection from a first holder to a second holder within a fluidprocessing device according to the invention;

FIG. 20C Schematic illustration of a first tube transfer from a firstholder of a first fluid processing device according to the invention toa second holder of a second fluid processing device;

FIG. 20D Schematic illustration of a first tube transfer from a firstholder of a fluid processing device according to the invention to aposition away from the centrifuge and back to a second holder of thefluid processing device.

DETAILED DESCRIPTION OF THE INVENTION

It is one aspect of the present invention to improve methods ofprocessing fluids that use centrifuges. For that purpose, the presentinvention provides fluid processing devices for use in a centrifuge. Afluid may be anything that is liquid independent of whether that liquidhas a high or low viscosity, or contains particles or solid elementsmoving within the liquid. The fluid processing devices according to theinvention may be used to manipulate or treat fluids by processes such asfiltering fluids, adsorbing specific elements of fluids to specificmaterials, desorbing specific elements from specific materials,separating components from fluids, collecting manipulated fluids, ordumping waste fluids. Preferably, the fluid processing devices accordingto the invention are used to purify biomolecules such as nucleic acids,proteins, peptides, polypeptides, nucleotides, and lipids.

In order to be usable in a centrifuge, it is further preferred that thefluid processing device is connectable to the rotor of the centrifuge.By having the centrifuge rotate the rotor, a centrifugal force can beapplied to the fluid processing device. Preferably, the connection tothe rotor is realized by connection means that may be part of the fluidprocessing device or not. If the connection means are not part of thefluid processing device, it is preferred that the connection means havea holding structure for removably holding the fluid processing device.In this case, and if the fluid processing device includes a firstcontainer, the elements that are integrally connected with the firstcontainer form a unit that is below referred to as first containercomprising structure.

A holding structure for removable holding the fluid processing devicemay be realized in different ways that are known in the art. Forexample, the holding structure may be form-fit to the outer shape of thefluid processing device so that it can receive and carry the fluidprocessing device securely even during centrifugation. Other methods forthe holding structure to hold the fluid processing device may beclamping, locking and so on.

Independent of whether the connection means are part of the fluidprocessing device or not, it is preferred that the connection meansfacilitate a removable connection of the fluid processing device withthe rotor. This way, it is possible to connect a fluid processing deviceto the rotor for carrying out a centrifugal step and, thereafter, toremove the fluid processing device from the centrifuge to performfurther steps with the fluids outside of the centrifuge. In particular,by having the fluid processing device being removably connectable to therotor, the fluid processing devices may be used as disposables. Havingdisposable fluid processing devices helps reducing sample contaminationcaused by reuse and increasing process safety and safety for theoperating personnel. Further it may save time as loading of the fluidprocessing devices needed for the next processing sequence can beperformed outside the centrifuge during an ongoing processing sequence.

It is further preferred that the fluid processing device is smallcompared to the rotor so that multiple fluid processing devices can beconnected to the rotor at a time. This way, multiple fluid samples canbe centrifuged at a time within a centrifugal step to increasethrough-put. Also, if the fluid processing devices are used asdisposables, i.e. as a one-time-use article, it may save costs to keepthe fluid processing devices small.

According to one aspect of the invention, the fluid processing deviceincludes a first holder for holding a first tube and a second holder forholding a second tube. Preferably, the first holder is capable ofholding the first tube at a first holding position with respect to thesecond holder, preferably at rest and during centrifugation.Analogously, it is preferred that the second holder is capable ofholding the second tube at a second holding position with respect to thefirst holder, at rest and during centrifugation. Therefore, it ispreferred that the first holder and the second holder are rigidlyconnected with each other. Further, it is preferred that at least one ofthe first holder and the second holder is made of one piece in order tobetter withstand deformation during centrifugation. It is furtherpreferred that the first and second holders are arranged with respect toeach other such that, if they hold a respective first and second tube,the two tubes are aligned in parallel. This way, it is easier todispense fluids into the respective tubes, or to place first and secondtubes into respective first and second holders.

It is generally preferred that at least one of the first holder and thesecond holder hold a respective first or second tube by mechanicalmeans. Preferably, at least one of the first holder and the secondholder is form-fit to the shape of the respective first tube or secondtube for holding respective first or second tube. For example, if thefirst tube has a cylindrical shape and a coaxial collar-like shaped rim(first collar), it is preferred that the first holder has a firstcylindrically-shaped inner face form-fit to the outer face of the firsttube. This way, the first tube can be slid into the first holder inwhich case the first tube's holding position is defined within a planeorthogonal to the sliding direction. Further, preferably, the first andthe second holder are rigid enough that they can hold a tube duringcentrifugation in a defined position at all swinging angles as at whichthe fluid processing device may be operated.

Further, it is preferred that the first holder provides for a firststopper that stops the sliding of the first tube into the first holder,e.g., by an engagement of the stopper with the first collar of the firsttube. This way, the first holding position of the first tube is definedin sliding direction. Further, with the first stopper stopping thesliding in one direction only, the first tube is removably connectedwith the first holder, i.e. the first tube can easily be slid out of thefirst holder again any time if needed. With the stopper and thecylindrically-shaped inner face of the first holder, the first holdingposition of the first tube can be maintained also during centrifugationprovided that the centrifugal force has a component pointing into thesliding direction.

Similarly, if the second tube has a cylindrical shape and a coaxialcollar-like shaped rim, it is preferred that the second holder has acylindrically-shaped inner face form-fit to the outer face of the secondtube. This way, the second tube can be slid into the second holder inwhich case the second tube's holding position is defined within a planeorthogonal to the sliding direction.

Further, it is preferred that the second holder provides for a secondstopper that stops the sliding of the second tube by an engagement ofthe stopper with the coaxial collar-like shaped rim (second collar) ofthe second tube. This way, the second holding position of the secondtube is defined within the sliding direction. Further, with the secondstopper stopping the sliding in one direction only, the second tube isremovably connected with the second holder, i.e. the second tube caneasily be slid out of the second holder again any time if needed. Withthe stopper and the cylindrically-shaped inner face of the secondholder, the second holding position of the second tube can be maintainedas long as centrifugal and/or gravitational force has a componentpointing into the sliding direction.

The use of the words “first tubes” and “second tubes” is to beunderstood in a broad sense. A tube can be any container in which afluid can be dispensed through an inlet opening. Preferably, the firsttube and the second tube are rotationally symmetrical with respect torespective first or second axes. For example, a tube may have acylindrical shape having an inlet opening at one end, a conical shapehaving an inlet opening at one end, or a combination thereof. Further,the cylindrical or conical shapes may have cross sections orthogonal torespective first or second axis that are circular, elliptical, squared,rectangular or combinations thereof. Preferably, the first cross sectionof the first tube is defined at the first tube's position where thefirst tube is held by the first holder. Analogously, it is preferredthat the second cross section of the second tube is defined at thesecond tube's position where the second tube is held by the secondholder.

Preferably, the first cross section of the first tube and the secondcross section of the second tube are adapted to each other such that thefirst tube can be slid into the second tube via the inlet opening of thesecond tube. It is further preferred that the outer face of the firsttube is form-fit to the inner face of the second tube. This way, thesecond tube can be used as a holder for holding the first tube duringcentrifugation. Even more, with the second holder holding a second tubeand the second tube holding a first tube, the second holder of the fluidprocessing device can be used for holding the first tube duringcentrifugation. In this case it is preferred that the cross section ofthe first cylindrically-shaped inner face of the first holder is smallerthan the cross section of the second cylindrically-shaped inner face ofthe second holder by not more than 60%, preferably not more than 50%,and even more preferred not more than 40%. On the other hand, in thiscase, it is preferred that the cross section of the firstcylindrically-shaped inner face of the first holder is smaller than thecross section of the second cylindrically-shaped inner face by more than10%, preferably more than 20%, and even more preferred more than 30%.Preferably, the cross section of the first tube has an area that islarger than 10 mm², preferably larger than 40 mm² and possibly largerthan 80 mm². On the other hand, it is preferred that the cross sectionof the first tube has an area that is smaller than 1000 mm², preferablysmaller than 100 mm² and possibly smaller than 60 mm².

In a preferred embodiment of the invention, the first tube has an inletopening and an outlet opening. Those tubes are also known as columns orspin columns. Further, preferably, the first tube has a filter elementseparating the inlet opening from the outlet opening. Preferably, thefilter element also acts as a membrane for selectively bindingbiomolecules like nucleic acid. This way, the first tube can be used fora binding step where, by dispensing a biomolecule containing fluid intothe inlet opening of the first tube and letting it pass through,biomolecules are selectively bound to the filter element.

On the other hand, it is preferred that the second tube is used forcollecting a fluid (collection tube). In this case, it is preferred thatthe second tube has an inlet opening but no outlet opening. In thiscase, the second tube can be used for the elution step by collecting theelution fluid including the purified biomolecules that has been elutedfrom the filter element of the first tube.

In a preferred embodiment of the invention, the fluid processing deviceincludes a first container having a first container volume for holding afluid. Preferably, the first container is rigidly connected with thefirst holder. Preferably, the first container is arranged with respectto the first holder such that a fluid flowing through the first tubeheld by the first holder flows into the first container. Preferably, thefluid flows through the first tube because it is drained bygravitational or centrifugal force. This way, by collecting the fluidsthat have passed through the first tube into the first container (e.g. awaste fluid during a washing step), cross contamination with adjacenttubes during centrifugation can be eliminated. Further, with asufficient large first container volume, binding and washing can becarried out without having to interrupt centrifugation for discardingthe collected fluid. This helps reducing time consuming unloading andloading steps of the centrifuge, and makes it possible to increase thenumber of washing steps or to increase the lysate volume. Preferably,the first container volume is larger than 1 ml, preferably larger than10 ml and possible larger than 50 ml. On the other hand, it is preferredthat the first container volume is smaller than 100 ml, preferablysmaller than 50 ml and possibly smaller than 10 ml. Preferably, thecontainer volume is defined by the amount of fluid that the firstcontainer can hold during centrifugation. On the other hand, the volumeof the first container that is actually used for a process, i.e. the netvolume of the first container, is preferably smaller than the firstcontainer volume by at least 25%, preferably by at least 50%, and evenmore preferred by at least 75% of the first container volume. This is toavoid that the outlet openings of the first and/or second tubes get incontact with the fluid held within the first container (e.g. wastefluid) during the process in order to prevent contamination of the tubeswith the fluid held within the first container and spillage of the fluidduring centrifugation.

Preferably, the first container volume is larger than the volume of thesecond tube to allow for binding and washing steps without interruptionsdue to discarding the fluid that has flown into the first container. Forthat purpose, it is preferred that the first container is designed suchthat the inner surface of the first container adjoins to the secondholder. This way, the first container volume can be maximized at a givensize of the fluid processing device. Further, in order to maximize thefirst container volume, it is preferred that the ratio of the weight ofthe fluid processing device to the volume of the first container issmaller than 10 g/cm³, preferably smaller than 5 g/cm³ and even morepreferred smaller than 1 g/cm³. In a preferred embodiment, the fluidprocessing device weighs 7.23 g and has a container volume of about 11cm³ which results in a ratio of 0.66 g/cm³.

The following figures disclose schematically some of the embodimentsaccording to the invention in order to illustrate several aspects of theinvention. The details and features of the drawings and description,however, should not be understood as limiting the scope of theinvention. For example, while the embodiments are disclosed inconnection with a particular set of tubes for clarity sakes, theinvention is not limited to the use of this particular set of tubes.Also, while the fluid processing device's elements (e.g. the firstholder, the second holder, the first container, the second container andso on) in the figures are connected by bold lines, this is merely to beunderstood schematically to indicate a rigid connection. However,depending on the application and other circumstances, a skilled personunderstands from the figures that there are many different geometriesand shapes in which the fluid processing device's elements can beconnected for use in a centrifuge.

FIGS. 1A-1E disclose a first example of a tube set that can be used forpurifying biomolecules according to the present invention. The tube setconsists of a first tube 18 as shown in FIGS. 1A-1B and a second tube 26as shown in FIGS. 1C-1D. First tube 18 is rotational symmetric withrespect to first axis 11 and has a circular first cross section A1 (seeFIG. 1B) in a direction orthogonal to first axis 11. First tube 18further has a first inlet opening 54, a first outlet opening 52, afilter element 19 through which a fluid that has been dispensed intoinlet opening 54 flows in order to reach first outlet opening 52, acollar-like shaped rim (first collar) 56, and, optionally, a first cap40 that is flexibly connected to collar 56. First cap 40 can be used toclose the inlet opening 54 in order to avoid contamination of the tubecontent. In the case of the tube set of FIGS. 1A-1E, filter element 19is a matrix material for binding biomolecules, for example nucleicacids, to the filter when a biomolecule containing fluid is dispensedinto inlet opening 54.

Second tube 26 of FIGS. 1C-1D is rotational symmetric with respect tosecond axis 27. Second tube 26 further has circular second cross sectionA2 (see FIG. 1D) orthogonal to second axis 27, a second inlet opening 58but no outlet opening (closed tube). Further, second tube 26 has acollar-like shaped rim (second collar) 59 and, optionally, a second cap41 that is flexibly connected to second collar 59. Second cap 41 is usedto close the inlet opening in order to avoid contamination of the tubecontent. The second cross section A2 of second tube 26 is sized suchthat first tube 18 can be slid into second tube 26 until first collar 56of first tube 18 hits second collar 59 of second tube 26 (see FIG. 1E).This way, second tube 26 can be used as a collection tube or containerfor receiving a fluid dispensed into inlet opening 54 of first tube 18,as well as a holder for holding first tube 18 during centrifugation.

Tubes as shown in FIGS. 1A-1E are commercially available at differentsizes and filter materials depending on the application. For example,applicant's QIAprep Spin Miniprep Kit™ offers spin columns (first tubes)having a cross section A1 of 8.8 mm and a length of 30 mm, andcollection tubes (second tubes) having a cross section A2 of 10.5 mm anda collection volume of about 2 ml.

FIGS. 2A-2E disclose schematically a first fluid processing deviceaccording to the invention. FIG. 2A shows a cross sectional side-viewalong axis C1-C1′ of fluid processing device 1 holding a first tube 18and a second tube 26 of the types as shown in FIGS. 1 A and 1C. FIG. 2Bshows a corresponding cross section along axis C1-C1′ in a directionorthogonal to the side view of FIG. 2A. The fluid processing device 1 iscomprised of a first holder 14 at a first holding position 16 and asecond holder 22 at a second holding position 24 that are rigidlyconnected with each other. Further, as mentioned before, fluidprocessing device 1 can be connected to the rotor of a centrifuge bymeans of connection means (not shown) in ways that will be describedlater in more details.

As can be seen from FIGS. 2A and 2B, first holder 14 comprises acylindrically-shaped ring-element having an inner face form-fit to theshape of a portion of first tube 18 to hold first tube 18 at a definedfirst holding position 16 with respect to the second holder 22. Thering-element of first holder 14 further provides a first stopper 60which in FIGS. 2A-2E corresponds to the upper rim of the first holder'sring-element. This way, first tube 18 can be slid into the ring-elementuntil first collar 56 of first tube 18 hits the ring-element. This way,first tube 18 is held by first holder 14 as long as gravitational orcentrifugal forces have a component in sliding direction, i.e. downwardin FIG. 2A Further, first tube 18 can easily be removed from firstholder 14 by sliding first tube 18 out of the ring-element. It isself-understood that the cylindrically-shaped ring-element is shaped andrigid enough that it can hold a tube during centrifugation in a definedposition at all swinging angles as at which the fluid processing devicemay be operated.

Similarly, second holder 22 is a cylindrically-shaped ring-elementhaving an inner face form-fit to the shape of a portion of second tube26 to hold second tube 26 at a defined second holding position 24 withrespect to the first holder 14. The ring-element of second holder 22further provides a second stopper 62 which in FIGS. 2 A-E corresponds tothe upper rim of the second holder's ring-element. This way, second tube26 can be slid into the ring-element until second collar 59 of secondtube 26 hits the ring-element. This way, second tube 26 is held bysecond holder 22 as long as gravitational or centrifugal forces have acomponent in sliding direction. Further, second tube 26 can easily beremoved from second holder 22 by sliding second tube 26 out of thering-element.

Further, first holder 14 and second holder 22 are each rigidly connectedwith each other to provide for a sufficient stiffness when beingcentrifuged. Further, first holder 14 and second holder 22 are orientedwith respect to each other such that they hold the two tubes 18, 26 inparallel. A parallel orientation of the first tube and second tube withrespect to each other simplifies dispensing of fluids into respectivetubes and automatic transfer of the first tube to the second tube.

FIG. 2C illustrates a side view of fluid processing device 1 of FIG. 2Awith the first and second tubes removed. Like for the other fluidprocessing devices in this application, it is preferred that the fluidprocessing device 1 of FIG. 2C is compression-molded from polymericmaterial and, preferably, made of one piece in order to improve rigidityand reduce weight and costs.

FIG. 2D-2E illustrate a direct transfer 30 (first tube transfer) offirst tube 18 from first holding position 16 to second holding position24. With the direct transfer 30 and the second tube 26 in place at thesecond holding position 24, binding and washing steps performed withfirst tube 18 at first holding position 16 can be followed by an elutionstep at second holding position 24 without the steps of (a) taking firsttube 18 out of the centrifuge for placing the first tube 18 into asecond tube; and (b) placing second tube 26 together with first tube 18back to the centrifuge. Rather, with the fluid processing device ofFIGS. 2A-2E, the elution step can be made to follow the binding andwashing steps by applying three first tube movements: (a) sliding firsttube 18 out of first holder 14, i.e. a movement in axial direction offirst tube 18 (z-direction); (b) moving first tube 18 from first holdingposition 16 to second holding position 24, i.e. a movement lateral tothe axial direction (x-direction); and (c) sliding first tube 18 intosecond tube 26, i.e. a movement in axial direction of first tube 18(negative z-direction). Accordingly, the direct transfer of first tube18 includes only two axial movements, one in z-direction and the otherin negative z-direction. The way in which first tube 18 is inserted intosecond tube 26 and held in position has been described earlier in FIGS.1A-1E.

Further, with first tube 18 placed into second tube 26, elution can becarried out by dispensing an elution fluid into the inlet opening offirst tube 18 and carrying out a further centrifugation step. With thecentrifuge exerting a centrifugal force in axial direction towards thefirst tube's outlet opening 52, the elution fluid is pressed throughfilter element 19, desorbs the bound biomolecules, e.g. nucleic acid,from filter element 19, leaves first tube 18 and is received by secondtube 26 which in this case acts as a second container 64 or collectiontube. This way, the purified biomolecules are collected in second tube26 (i.e. second container 64) for further processing. Note that, sincesecond tube 26 can be removed from fluid processing device 1 and sincesecond tube 26 preferably is a standard tube, further processing of theeluate is simpler because of the second tubes compatibility with otherlab equipment that may be used for the further processing of the eluate.

FIGS. 3A-3E disclose schematically a second fluid processing deviceaccording to the invention. FIG. 3A shows a cross sectional side-viewalong axis C1-C1′ of the fluid processing device 1 holding a first tube18 and a second tube 26 of the types as shown in FIGS. 1 A and 1C. FIG.3B shows a corresponding cross section along axis C1-C1′ in a directionorthogonal to the side view of FIG. 3A. The fluid processing device 1 ofFIGS. 3A-3E is identical to the one shown in FIGS. 2A-2E except that thefluid processing device 1 of FIGS. 3A-3E has a first container 10rigidly connected with first holder 14 and second holder 22. Firstcontainer 10 is positioned with respect to first holder 14 such that afluid flowing through first tube 18 held by first holder 14 flows intofirst container 10. This way, fluids (e.g. lysate or wash buffers) thathas been dispensed into first tube 18 at first holding position 16 forthe binding and washing steps, and that has passed through filterelement 19, can be collected within first container volume 12 of firstcontainer 10 as waste. First container 10 therefore may also beconsidered as waste container. By designing first container 10 largeenough, binding and washing can be carried out without having tointerrupt those processes for discarding the waste. Discarding wastewould imply time consuming unloading and reloading of the centrifuge.Further, a sufficiently large waste container 10 allows for additionalwashing steps etc. without having to go through time consuming wastediscarding steps.

First container 10 is preferably rigidly connected with first holder 14and second holder 22 to form a first container comprising structure 103that is rigid enough to withstand high centrifugal forces. It is notnecessary, but preferred, that first container 10, first holder 14 andsecond holder 22 are made of one piece for stability and formanufacturing reasons. Further, first container 10 may be a hermeticallyclosed container, with the exception of the opening provided by firstholder 14. This would provide for a particular stable structure andprotect the surroundings from spilled waste fluid. However, as it hasturned out, it is not necessary for most processes to have ahermetically closed container. Further, manufacturing of the fluidprocessing device in one piece is less expensive if the first containeris open in the top region. Furthermore, it may be necessary to haveaccess to the waste fluid for control purposes.

FIGS. 3D-3E illustrate, like FIGS. 2D-3E, a direct first tube transfer30 of first tube 18 from first holding position 16 to second holdingposition 24. Again, with the fluid processing device of FIGS. 3A-3E, theelution step can be made to follow the binding and washing steps byapplying a direct transfer 30 with three first tube movements: (a)sliding first tube 18 out of first holder 14; (b) moving first tube 18from first holding position 16 to second holding position 24; and (c)sliding first tube 18 into second tube 26. However, different from FIGS.2A-2E, there is first container 10 that can receive filtered fluids(lysate or wash fluids), i.e. waste fluid, that has left first tube 18through its filter element 19. This way, waste fluid can be discarded ina way that it does not contaminate other tubes or fluids. Further,discarding is carried out without having to unload or reload the firsttubes out of or into the centrifuge.

FIGS. 4A-4E disclose schematically a third fluid processing deviceaccording to the invention. FIG. 4A shows a cross sectional side-viewalong axis C1-C1′ of the fluid processing device 1 holding a first tube18 and a second tube 26 of the types as shown in FIGS. 1A and 1C. FIG.4B shows a corresponding cross section along axis C1-C1′ in a directionorthogonal to the side view of FIG. 4A. The fluid processing device 1 ofFIGS. 4A-4E is the same as shown in FIGS. 3A-3E with the difference thatfirst container 10 is extended to overlap second holder 22 in aprojection orthogonal to first axis 11 of first tube 18 when held byfirst holder 14. This way, inner surface 10 a of first container 10adjoins to second holder 22. The design helps to significantly increasefirst container volume 12 to allow for more waste without having toincrease the height of the container. Increasing the height of the firstcontainer would require the use of larger centrifuges. Further, with theshown extension of first container 10 to second holder 22, second holder22 is connected more rigidly to first holder 14 to minimize deformationof fluid processing device 1 during centrifugation.

Fluid processing device 1 of FIGS. 4A-4E differs further from theembodiments of FIGS. 2 a-2E and 3A-3E in that second holder 22 isform-fit to first tube 18 having a first cross section A1, instead ofholding a second tube 26 having a second cross section A2. This way, thecylindrically-shaped inner faces of first holder 14 and the one ofsecond holder 22 have the same axial cross sections. Further, differentfrom the previous designs, second holder 22 extends into first container10 to form a second container 64 having a second container volume 65.This way, for carrying out the binding, washing and elution steps, nosecond tube 26 is required since the purified biomolecules can be elutedinto second container 64. However, since in this case second container64 is rigidly connected with first holder 22 and first container 10,fluid processing device 1 has to be taken out of the centrifuge forfurther processing of the purified biomolecules. Furthermore, thisembodiment is not suitable if storage of the purified biomolecules isdesired.

FIG. 4C illustrates a side view of fluid processing device 1 of FIG. 4Awith the first tube removed. Again, preferably, the fluid processingdevice 1 as shown in FIG. 4C is made of one piece (first containercomprising structure 103) in order to improve rigidity of the device andto reduce costs. Further, FIGS. 4D-4E illustrate, like FIGS. 3D-3E, adirect transfer 30 (first tube transfer) of first tube 18 from firstholding position 16 to second holding position 24.

FIGS. 5A-5E disclose schematically a fourth fluid processing deviceaccording to the invention. FIG. 5A shows a cross sectional side-viewalong axis C1-C1′ of the fluid processing device 1 holding a first tube18 and a second tube 26 of the types as shown in FIGS. 1A and 1C. FIG.5B shows a corresponding cross section along axis C1-C1′ in a directionorthogonal to the side view of FIG. 5A. The fluid processing device 1 ofFIGS. 5A-5E is the same as shown in FIGS. 4A-4E with the difference thatsecond holder 22 is not extended to form a second container. Instead,for providing a second container 64 for elution, a second tube 26 needsto be inserted into second holder 22. Accordingly, in order to advancefrom the binding and washing steps to the elution step, first tube 18has to be transferred from first holder 14 to second holder 22 and beslid into second tube 26 as disclosed in FIG. 1E. In this case, secondtube 26 holds first tube 18 and, at the same time, serves as a secondcontainer for holding the elution fluid flowing through first tube 18.Further, since second tube 26 can be removed from fluid processingdevice 1, the eluted fluid with the eluted biomolecules can be removedfrom fluid processing device 1 for further processing or storagepurposes without having the fluid processing device 1 to remove from thecentrifuge.

FIG. 5C illustrates a side view of fluid processing device 1 of FIG. 5Awith first tube 18 and second tube 26 removed. Again, preferably, thefluid processing device 1 as shown in FIG. 5C is made of one piece(first container comprising structure 103) in order to improve rigidityof the device and to reduce costs. Further, FIGS. 5D-5E illustrate, likeFIGS. 4D-4E, a direct transfer 30 (first tube transfer) of first tube 18from first holding position 16 to second holding position 24.

FIGS. 6A-6E disclose schematically a fifth fluid processing deviceaccording to the invention. FIG. 6A shows a cross sectional side-viewalong axis C1-C1′ of the fluid processing device 1 holding a first tube18 at a first holding position 16 and a second tube 26 at a secondholding position 24. FIG. 6B shows a corresponding cross section alongaxis C1-C1′ in a direction orthogonal to the side view of FIG. 6A. Thefluid processing device 1 of FIGS. 6A-6E is the same as shown in FIGS.5A-5E with the difference that a third holder 66 has been added forholding a third tube 32 having a third axis 34, a third cross section A3and a third collar 33 at the tube's rim.

In FIG. 6A, third tube 32 is a further spin column having a third inletopening, a third outlet opening and a filter element. In manyapplications, the geometry of the third tube 32 equals the geometry ofthe first tube 18 so that the third cross section A3 is the same as thefirst cross section A1. However, depending on the application, firsttube 18 and third tube 32 may differ by their filter element type. Notethat, if the first cross section A1 and the third cross section A3 arethe same, the inner face of first holder 14 may be the same as the innerface of third holder 66 so that the first tube 18 may also be held bythird holder 66 and the third tube 32 may be also held by the firstholder 14 if required by the process.

Further, third holder 66 is extended to provide for a third container 68having a third container volume 70. Further, depending on theapplication, third holder can be made to hold a first tube 18 having afirst cross section A1 or to hold a second tube 26 having a second crosssection A2. As can be seen from the figures, third holder 66 has acylinder-like shaped inner face that is form-fit to the shape of thirdtube 32. This way, by sliding third tube 32 into the inner cylinder-likeshaped face, third tube's 32 position is defined within a planeorthogonal to the sliding direction. Further, the upper rim of thecylinder-like shaped face of third holder 32 is such that it functionsas a third stopper 67 that stops the sliding of third tube 32 into thirdholder 66 at the moment when third collar 33 hits stopper 67. In thisposition, third tube's 32 position is also defined in sliding directionas long as gravitational or centrifugal forces have a component pressingthird collar 33 onto third stopper 67. Again, it is preferred that thirdholder 66 is arranged such that it holds third tube 32 such that thirdtube 32 is in parallel to first tube 18 when held by first holder 14.

Third holder 66 is useful for implementing additional purification stepsinto the fluid processing device 1. For example, some applicationsrequire additional filter elements with different functionalities. Thirdholder 66 can be used for holding a third tube 32 with a filter elementdiffering in its specificity or functionality from the filter element offirst tube 18. Third tube 32 is arranged in a way that a fluidcontaining the desired biomolecules flows through third tube 32 intothird container 70 when held by third holder 66 in third holdingposition 28. Before gaining access to the fluid containing the desiredbiomolecules the third tube 32 has to be removed from the third holder66.

Further, third holder 66 can be used without another filter element forlysate clearing after lysis of an initial biological sample beforeperforming the binding, washing and elution steps. Lysing of thebiological sample may be carried out separately, for example, bydispensing a lysing buffer to the sample fluid in order to break up thecell walls of the cells containing biomolecules, e.g. nucleic acids.After addition of a further buffer, for example a neutralization buffer,the lysat is transferred into the third container volume 70 of thirdcontainer 68. In order to pellet the cell debris in third container 68centrifugal force is applied to the fluid processing device 1, and thesupernatant containing biomolecules, i.e. the cleared nucleic acidcontaining fluid, is pipetted from third container 68 into first tube 18to initiate the binding step.

Note that the above method would also work with a third tube 32 if thirdtube 32 is formed as a container and placed in the third holdingposition 28. In this case the initial biological sample is dispensedinto the third tube 32 after lysis.

Also note that, as can be seen from FIGS. 6A-B, first container 10 isextended in a projection orthogonal to first axis 11 of first tube 18held by first holder 14 in a way that it covers second holder 22 andthird holder 66. Again, this is to maximize the first container volume12 at a given container height in order to maximize the waste volume.

FIG. 6C illustrates again a side view of fluid processing device 1 ofFIG. 6A with first tube 18, second tube 26 and third tube 32 removed.Again, preferably, the fluid processing device 1 as shown in FIG. 6C ismade of one piece (first container comprising structure 103) in order toimprove rigidity of the device and to reduce costs. Further, FIGS. 6D-6Eillustrate, like FIGS. 5D-5E, a direct transfer 30 (first tube transfer)of first tube 18 from first holding position 16 to second holdingposition 24 for the elution step.

FIG. 7A-7B illustrates two orthogonal cross sections through a sixthfluid processing device 1 according to the invention. The fluidprocessing device 1 of FIG. 7A-7B is the same as the one of FIGS. 6A-6Fexcept that it contains a fourth holder 80 for holding a further firsttube 18. The further first tube 18 is held by holder 80 such that afluid flowing through further first tube 18 holder also flows into firstcontainer 10. With the first holder 14 holding a first tube 18 andfourth holder 80 holding a further first tube 18, it is possible to bindand wash two different biomolecules at a time.

FIGS. 8A-8B illustrate two orthogonal cross sections through a seventhfluid processing device 1 according to the invention. Fluid processingdevice 1 of FIGS. 8A-8B is identical the embodiment of FIGS. 7A-7E withthe exception that it includes a fifth holder 90 holding a furthersecond tube 26. This embodiment is to show that the present inventionallows including at least five holders, e.g. two holders for holding afirst tube 18, two holders for holding a second tube 26 and one tube forholding a third tube 32. Depending on a process sequence and on the sizeof the centrifuge to be used, if multiple holders are required tosimplify the process sequence, the present invention enables theprovision of the required multiple holders of different sizes. Also,while in the figures of the description the various holders are linearlyaligned along axis C1-C1′, it is also possible to arrange holdersdistributed within two dimensions, e.g. within two lines or as anarbitrary array.

The fluid processing devices described so far do not include connectionmeans. However, as mentioned before, with connection means that have aholding structure for holding the fluid processing device 1, it ispossible to connect those fluid processing devices to the rotor, as askilled person will know.

FIGS. 9A-8B illustrate two orthogonal cross sections through an eighthsfluid processing device 1 according to the invention. The eighths fluidprocessing device is identical to the embodiment of FIGS. 3A and 3B withthe difference that the present embodiment comprises connection means104 for connecting fluid processing device 1 to a rotor of a centrifuge.In the present case, connection means 104 consist of two swing axleelements 105 that are integrally connected with two opposing sides offirst container 10. The two swing axle elements 105 are shaped like twofrusta pointing outwardly with respect to first container 10 to defineswing axis 106 that extends through first container volume 12. As willbe shown later in more detail, in order to removably connect fluidprocessing device 1 to a rotor of a centrifuge, the two frusta-shapedswing axle elements 105 are hung into respective receiving rotorconnection means 134, e.g. swing axle receivers 128, that are part oftwo opposing arms of the rotor.

Swing axle elements 105 of fluid processing device 1 and receiving rotorconnection means 134, e.g. swing axle receivers 128, of the rotor arepositioned and adapted with respect to each other such that fluidprocessing device 1 can turn around a swinging axis 106 that extends intangential direction with respect to the rotation of the rotor in thecentrifuge. This way, one or more of the fluid processing devices 1 ofFIGS. 9A-9B can be centrifuged in a way that the fluid processingdevices are free to swing outwardly around swinging axis 106 dependingon the centrifugal force. This way, if the centrifugal force is veryhigh compared to the gravitational force, the fluid processing devicesmay swing so far outwardly that the tubes have an almost horizontalorientation. In this case, the fluids within the first and second tubesare pressed under centrifugal force in almost axial direction towardsthe tube's floor or through the tube's filter element. Generally, it ispreferred that swing axle elements 105, e.g. two frusta or cylinders,are integrally connected with first container 10, first holder 14 andsecond holder 22. If this is the case, the fluid processing device 1 issaid to be self-supported. In a preferred embodiment, however, the fluidprocessing device 1 is not self-supported. In this case, it is preferredthat the connection means 104 have a holding structure 102 that isadapted for holding the fluid processing device 1 during centrifugationas shown, for example, in FIG. 12.

It should be mentioned that the use of cylindrically or frusta-shapedswing axle elements 105 is only one of many ways to implement a swingingfluid processing device 1 to a rotor of a centrifuge. For example,instead of swing axle elements 105 pointing outwardly with respect tofirst container 10, two recesses at the respective sides of firstcontainer 10 can be used that are shaped to engage with the receivingrotor connection means 134, e.g. swing axle receivers 128, of the rotorsuch that fluid processing device 1 can swing outwardly undercentrifugal force. Further, it is also possible to place swing axleelements 105 in such a way with respect to first container 10 that theydefine a swinging axis 106 that runs outside of first container volume12. In this case, the connection means 104 may use a hinge joint that isbiased by a spring for making a swinging connection with the rotor,instead of using a frusta-shaped swing axle element.

FIGS. 10A-10B illustrate two orthogonal cross sections through a ninthfluid processing device 1 according to the invention. Fluid processingdevice 1 of FIGS. 10A-10B is identical to the embodiment of FIGS. 4A-4Ewith the exception that, like in FIGS. 9A-9B, the fluid processingdevice 1 is self-supported because of the integrally connected twofrusta 105 for connecting fluid processing device 1 with a rotor of acentrifuge.

FIGS. 11A-11B illustrate two orthogonal cross sections through a tenthfluid processing device 1 according to the invention. Fluid processingdevice 1 of FIGS. 11A-11B is similar to the embodiment of FIGS. 6A-6Ewith the exception that, like in FIGS. 10A-10B, the fluid processingdevice 1 is self-supported because of its integrally two frusta 105 forconnecting fluid processing device 1 with a rotor of a centrifuge.

FIG. 12 discloses an eleventh fluid processing device according to theinvention that is identical to the embodiment according to FIGS. 11A-11Bexcept that connection means 104 comprise in addition to swing axleelements 105 a holding structure 102 for holding first container 10 withfirst holder 14, second holder 22 and third holder 66. In this case,connection means 104 and the structure comprising first container 10 canbe considered as separate units that are adapted to each other to beremovable connectable with each other. Further, in FIG. 12, the innerface of holding structure 102 is form-fit to the outer face 10 b offirst container 10 to make sure that holding structure 102 and firstcontainer comprising structure 103 are in a defined position withrespect to each other, at rest as well as during centrifugation. On theother hand, for simplifying handling, it is preferred that holdingstructure 102 has an opening large enough so that first containercomprising structure 103 can be removed from holding structure 102 bysimply extracting first container comprising structure 103 from holdingstructure 102. For example, in FIG. 12, holding structure 102 iscup-shaped with the inner face of the cup form-fit to the outer shape offirst container 10. This way, first container comprising structure 103consisting of first container 10, first holder 14, second holder 22, andthird holder 66 can be separated from cup-shaped holding structure 102by extracting the two from each other.

In a preferred embodiment, first container comprising structure 103 andholding structure 102 are shaped such that first container comprisingstructure 103 can be inserted into holding structure 102 at only oneorientation with respect to each other. This is to prevent that, e.g., auser confuses first and second tubes by inserting the containercomprising structures into holding structures accidentally at differentorientations.

In a further preferred embodiment, first container comprising structure103 and holding structure 102 are shaped such that it is possible toinsert first container comprising structure 103 into holding structure102 at two different orientations, preferably at an angle of 180 degreesbetween the two orientations. The two orientations can be used to allowthe connection means 104 to be connected with the rotor of thecentrifuge in two opposite directions. This in turn makes it possiblethat the fluid processing devices in the rotor can be centrifuged at twodifferent predetermined swinging angles as (see FIG. 18C), depending onthe chosen orientation. The predetermined swinging angle as indicatesthe maximum angle at which the fluid processing devices swing within therotor arms 126, with respect to the orientation at rest.

It should be noted that it is preferred that connection means 104comprising holding structure 102 and swing axle elements 105 are made ofone piece. Further, in order to withstand the centrifugal force exertedto first container comprising structure 103, it is preferred thatholding structure 102 is made of a material that is light but has a highstrength, e.g. aluminum. Also, if the first container comprisingstructure 103 is removable from holding structure 102, it may be anoption that swing axle elements 105 and receiving rotor connection means134, e.g. swing axle receiver 128, are adapted to provide for apermanent connection.

FIG. 13 discloses a twelfth fluid processing device according to theinvention that is identical to the embodiment according to FIG. 12except that the present fluid processing device 1 includes first capfixture means 44 for holding a first cap 40 of a first tube 18 duringcentrifugation and second cap fixture means 46 for holding a second cap41 of a second tube 26 during centrifugation. With the first cap fixturemeans 44 and the second cap fixture means 46 it is possible tocentrifuge tubes with an open inlet opening, i.e. centrifuging tubesthat have a cap connected to it with their caps taken off. Centrifugingtubes with an open inlet opening is advantageous since, whenautomatically transferring first tube 18 from first holder onto secondtube 26, no step for taking off second cap 41 from second tube 26 isrequired. Further, with an open first tube, it is not necessary to takeoff first cap 40 from first tube 18 in order to withdraw or dispense afluid from or into the first tube 18. This significantly simplifiesautomation.

In FIG. 13, first cap fixture means 44 are realized by providing a capenclosure structure 50 in which first cap 40 can be slid in at the sametime as first tube 18 is slid into first holder 14. With first cap 40slid into cap enclosure structure 50, first cap 40 does not have thefreedom anymore to freely move during centrifugation. This is to avoidany damage that a freely moving cap that is flexibly connected to a tubecould cause during centrifugation. Preferably, cap enclosure structure50 is integrally connected with first holder 14. Of course, a skilledperson will know what shape and size to choose for the cap enclosurestructure 50 depending on the type of tube that is to be held.

Similarly, second cap fixture means 46 in FIG. 13 are realized byproviding a cap enclosure structure 50 in which second cap 41 can beslid in at the same time as second tube 26 is slid into second holder22. Like for first tube 18, with second tube 26 slid into cap enclosurestructure 50, second cap 41 does not have the freedom anymore to freelymove during centrifugation to cause any damage. Further, like for firsttube 18, cap enclosure structure 50 of second cap fixture means 46 ispreferably integrally connected with second holder 14. Preferably, thefirst and second cap fixture means are mounted to the inner or outersurface 10 a, 10 b of the first container 10.

FIGS. 14A-14B disclose a further preferred embodiment according to theinvention in two orthogonal cross sections that in many ways resemblesthe embodiment according to FIG. 13. However, different from FIG. 13,the embodiment of FIGS. 14A-14B comprises two first cap fixture means 44a, 44 b of the kind as explained in FIG. 13. This way, it is possible tohave first cap 40 of first tube 18 held by first cap fixture means 44 inthe cases where first tube 18 is positioned in a first holding position16 as well as in a second holding position 24. This way, it is possibleto transfer first tube 18 with first cap 40 from first holder 14 forbinding and washing steps to second holder 22 for an elution stepwithout having to worry of any damage caused by a freely moving firstcap during centrifugation. It should be noted that for spatial reasons,the orientation of first first cap fixture means 44 a adjacent to firstholder 14 is rotated by approximately 145 degrees with respect to thesecond first cap fixture means 44 b adjacent to second holder 22. Thisimplies that, in order to transfer first tube 18 from first holder 14 tosecond holder 22, it is necessary to rotate first tube 18 byapproximately by 145 degrees for the second first cap fixture means 44 bto hold first cap 40. As shown in FIG. 13, other rotating angles arepossible as well.

The embodiment of FIGS. 14A-14B differs further from the embodiment ofFIG. 13 in that the three holders, i.e. first holder 14, second holder22 and third holder 66, have a cylindrical shape extending from thefloor of first container 10 to the stopper planes defined by respectivefirst, second and third stoppers 60, 62, 67 for holding respectivetubes. Further, in this embodiment, the outer wall of the cylindricallyshaped second holder 22, and the outer wall of cylindrically shapedthird holder, are in direct contact with the inner wall 10 a of firstcontainer 10. This arrangement provides for good strength againstdeformation due to centrifugal forces in the case that a large componentof the centrifugal force acts in axial direction of the tubes. It shouldbe noted that, in order to improve the rigidity of the fluid processingdevice 1 during centrifugation, it is generally preferred that more thanone, or all, of the cylindrically shaped holders are positioned withinfirst container 10 such that they are in direct contact with both theinner wall 10 a and the floor of first container 10.

It is further to be noted that the cylinder jacket of first holder 14 isprovided with a cylinder jacket slit 14 a extending in parallel to theaxis of the cylinder in order to provide for a fluid connection betweenfirst container volume 12 and the volume inside of cylinder jacket offirst holder 14. This ensures that fluid leaving outlet opening 52 offirst tube 18 at first holding position 16 flows outside of the cylinderinto first container volume 12. For example, if a binding and washingstep is carried out with first tube 18 at first holding position 16, thewaste fluid is free to leave the cylinder of first holder 14 throughcylinder jacket slit 14 a into first container volume 12.

FIG. 15 discloses a further fluid processing device 1 according to theinvention in which first stopper 60 of first holder 14 defines a firststopper plane 61 that is different from second stopper plane 63 definedby second stopper 62 of second holder 22. This way, it is possible tohold first tube 18 at a height different from the height of second tube26 as measured along the projections onto respective first or secondtube axes 11, 27. Holding first and the second tubes 18, 26 at differentheights provides for an option of easier accessing the tubes forremoving a tube from a holder or for placing a tube into a holder in thecase that first holder 14 and second holder 22 are positioned very closeto each other. Generally, it is preferred that the two stopper planes61, 63 are in parallel with each other since in this case, it is easierto transfer a first tube 18 from a first holder 14 to a second holder 22in an automated fashion.

FIG. 16 discloses a further variation of a fluid processing device 1according to the invention. Like in FIG. 15, fluid processing device 1has first holder 14 for holding a first tube 18 and second holder 22 forholding a second tube 26 and respective first and second stoppers 60, 62that define a first stopper plane 61 and a second stopper plane 63 thatdiffer from each other. However, different from FIG. 15, fluidprocessing device 1 includes a first container 10 whereby first holder14 is arranged with respect to first container 10 so that a fluidflowing through first tube 18 flows into first container 10. Further,first holder 14 is mounted to a wall of first container 10 while secondholder 22 is mounted to the floor of first container 10. This way, innersurface 10 a of first container 10 adjoins to first holder 14 and secondholder 22. Although not explicitly shown in FIG. 16, it is generallypreferred that the holders are in rigid contact with the side walls andthe bottom of the container.

FIG. 17A discloses a rotor according to the invention being part of acentrifuge (not shown). As a preferred embodiment this rotor is a rotor110 for rotating at least one fluid processing device 1 according to thepreceding description as well as according to any one of the claims 1 to73. This rotor 110 comprising rotor connection means 134 for connectingsaid fluid processing device 1 to said rotor 110 (as shown in FIG. 17B).Further this rotor 110 comprising rotor swing preventing means 132 forlimiting a rotation of said fluid processing device 1 around saidswinging axis 106 during centrifugation to a predetermined swingingangle (αs), whereby the predetermined swinging angle (αs) is preferably90 degrees and/or 45 degrees as e.g. described below. FIG. 17A showsrotor 110 carrying twelve identical fluid processing devices 1 of thetype, for example, as shown in FIG. 14A-14B with a first tube 18 held byfirst holder 14, second tube 26 held by second holder 22 and third tube32 held by third holder 66. First, second and third tubes 18, 26 and 32are rigidly connected with first container 10 having a first containervolume 12. FIG. 17A further discloses connection means 104 for eachfluid processing device 1 for connecting the first container comprisingstructures 103 with respective two rotor arms 126 via swing axle element105 and its counter part swing axle receiver 128. Swing axle receiver128 and swing axle element 105 are adapted to each other in such a waythat under centrifugal force, fluid processing device 1 swing inoutwards direction, i.e. around swinging axis 106 tangentially to therotation of the rotor rotating around rotation axis 120. Further, sincefirst container comprising structure 103 can be routinely extracted fromor inserted into holding structure 102 of connection means 104,connection means 104 may or may not be permanently connected to rotor110.

Rotor 110 has a rotation axis 120 that may be driven by the centrifuge'smotor to a speed exerting a centrifugal force to the fluid processingdevices of up to 10,000×g, preferably up to 20,000×g and even up to50,000×g or more, depending on the application. Further, the inventiondoes not depend on the number of fluid processing devices that can beconnected to the rotor at a time, i.e. the number may be one, four,eight, twelve, twenty four or higher depending on the application andthe size of the centrifuge.

FIGS. 17B-17C illustrate schematically two cross sections through rotor110 of FIG. 17A along the axes A-A′ and B-B′ respectively. FIG. 17Bshows a cross section along rotor arm 126 holding fluid processingdevice 1 (first dashed line in bold type) holding a first tube 18,second tube 26 and third tube 32. At rest, first tube 18, second tube 26and third tube 32 are oriented in gravitational direction. Further,rotor arm 126 radially extends to form a swing axle receiver 128 whichserves as a bearing for holding swing axle element 105 of fluidprocessing device 1. This way, by rotating rotor 110 around rotationaxis 120, centrifugal force forces fluid processing device 1 tooutwardly rotate around swinging axis 106 (see FIG. 14B). This way, thecentrifugal force can exert a pressure on the fluids in the tubes thatcompletely, or to a large extend, points in axial direction of thetubes. FIG. 17B also shows (thin dashed lines) swinging fluid processingdevice 1 a corresponds to fluid processing device 1 at a high rotationalspeed. In this case, swinging fluid processing device 1 a is rotatedoutwardly around swing axle element 105 by essentially 90 degrees withrespect to the fluid processing device's orientation at rest. Fluidprocessing devices 1 and 1 a are drawn in dashed lines since they do notlie within the plane of the cross section of FIG. 17B.

FIG. 17C shows a cross section through rotor 110 along axis B-B′ that isslightly shifted with respect to axis A-A′ (see FIG. 17A) to cut throughfluid processing device 1. FIG. 17C discloses first swing preventionmeans 108 for preventing a rotation, i.e. swinging, of fluid processingdevice 1 around swinging axis 106, e.g., during removal of first tube 18from first holder 14. In the case of FIG. 17C, first swing preventionmeans 108 acts through an engagement, or touching, of a swing preventionsection 10 c of first container 10 with rigid swing preventioncounterpart 111 that is part of the rotor and coaxially aligned withrespect to rotation axis 120. The engagement between swing preventionsection 10 c and swing prevention counterpart 111 prevents that fluidprocessing device 1 swings inwardly away due to a first frictional force113 generated between first tube 18 and first holder 14 duringextraction of first tube 18 from first holder 14.

FIG. 17C also discloses second swing prevention means 109 for preventinga rotation of fluid processing device 1 around swinging axis 106, e.g.due to a second frictional force 114 caused by inserting first tube 18into second holder 22. However, since second holder 22 is positioned onthe other side of swing axle element 105 and since second frictionalforce 114 points in opposite direction with respect to first frictionalforce 113, second swing prevention means 109 also have to prevent thatfluid processing device 1 swings away inwardly. Therefore, in thepresent case, second swing prevention means 109 and first swingprevention means 108 are the same. Preventing unintended swinging offluid processing device 1 during transfer of a tube from one holder tothe other is an important aspect of the invention when it comes toautomation of the transfer process.

Generally, a skilled person will understand that the swing preventionmeans can be obtained in various other related ways that use a suitableengagement between a swing prevention section and a swing preventioncounterpart. Also, while FIG. 17C discloses swing prevention section 10c integrally connected with first container 10, it may be advantageousto have the swing prevention section 10 c be part of a holding structure102 if there is a holding structure 102 for holding first container 10.

FIGS. 18A-18C illustrate the third swing prevention means 112 forlimiting a rotation of fluid processing device 1 around swinging axis106 during centrifugation to a predetermined swinging angle α_(s)between the directions given by the first tube at rest and duringcentrifugation (see FIG. 18C). Swinging axis 106 is defined byrespective two swing axle elements 105. Limiting swinging angle α_(s) isan important aspect of the invention since it has turned out that thefiltering effect to fluids may depend on the angle at which the fluidenter the filter element. Therefore, there is a desire to controlswinging angle α_(s).

In the case of FIG. 18A-18C, swinging angle limitation is realized byfirst edge 116 running in parallel to and protruding from the outersurface of holding structure 102 of connection means 104 (see FIG. 18A).Shape and orientation of first edge 116 are adapted to a second edge 118running in parallel to and protruding from the surface of an end ofrotor arm 126 (see FIG. 18B) in order to engage with each other or totouch each other as soon as during centrifugation, fluid processingdevice 1 has swung outwardly to predetermined swinging angle αs (seeFIG. 18C).

It should be noted that the predetermined swinging angle α_(s) isadjustable by choosing, for example, between different fluid processingdevices having their first edges 116 differently orientated on thesurface of the fluid processing device 1. With the first edges 116having different orientations, the fluid processing devices will engagewith the second edge 118 of the rotor 110 at a different swinging angleαs. However, as mentioned before, it is also possible to provide for twodifferent predetermined swinging angles with only one type of fluidprocessing device 1, or one type of connection means 104. A furtherexample for this concept may be a rotor 110 that has several swing axlereceivers 128 for each fluid processing device position wherein eachswing axle receiver 128 provides for a different predetermined swingingangle by having differently shaped swing prevention means.

Further, it should be noted that FIGS. 18A-18C also disclose a thirdedge 117 protruding from the outer surface of first container 10 (orholding structure 102) (see FIG. 18A) whose shape and orientation areadapted to a fourth edge 119 protruding from one side of rotor arm 126(see FIG. 18B) in order to engage with each other or touch each other assoon as rotor 110 of the centrifuge is at rest. This way, swinging offluid processing device 1 in inward direction is blocked. Accordingly,third edge 117 and fourth edge 119 represent a further embodiment of thefirst and second swing prevention means 108, 109 that were described inFIG. 17C.

FIGS. 19A-19B schematically disclose two methods according to theinvention in which a first tube (not shown) is automatically directlytransferred (direct first tube transfer 30) from a first holdingposition 16 within a centrifuge (not shown) to a second holding position24 within the centrifuge. In FIG. 19A, the direct first tube transfer 30is carried out in tangential direction with respect to the rotor'srotation in the centrifuge while in FIG. 19B, the direct first tubetransfer 30 is carried out in radial direction with respect to therotor's rotation in the centrifuge. Preferably, the direct first tubetransfer 30 is a transfer from a first holder 14 connected to rotor 110to a second holder 22 connected to rotor 110. Preferably, this transferis carried out without that, on its way from first holder 14 to thesecond holder 22, the first tube is transferred to a third holder thatis disconnected from rotor 110, e.g. a holder of a holding rack forholding tubes. With the automated first tube direct transfer 30, it ispossible to increase the speed for fluid processing since differentfluid processing steps can be carried out directly one after the otherwithout having to transfer the first tube away and back into thecentrifuge. For example, with the first tube held by first holder 14, itis possible to carry out the binding or washing steps with a fluidcontaining biomolecules while discarding the waste fluid into a firstcontainer. Then, after the direct transfer 30, with first tube held bysecond holder 22, it is possible to carry out the elution step in whichthe eluted fluid is collected in a second container or a second tube forfurther use.

FIGS. 20A-20D schematically disclose further methods according to theinvention in which a first tube (not shown) is automatically transferredfrom a first holder 14 of a fluid processing device 1 according to theinvention to a second holder 22 of the same fluid processing device 1(or of a second fluid processing device 1). In FIG. 20A-20D, eight fluidprocessing devices 1 according to the invention are disclosed that areconnected to rotor 110 which is connected to centrifuge (not shown) thatdrives the rotor. FIG. 20A discloses a direct transfer from a firstholder 14 of a fluid processing device 1 to a second holder 22 of thesame fluid processing device 1. Further, the direct transfer is atransfer in radial direction with respect to the rotation of rotor 110.FIG. 20B discloses the same direct transfer as in FIG. 20A with thedifference that the respective first and second holders within a fluidprocessing device 1 are separated in tangential direction with respectto the rotation of rotor 110. FIG. 20C discloses the same directtransfer as in FIG. 20A with the difference that the transfer is carriedout from a first holder of a first fluid processing device 1 to a secondholder of a second fluid processing device 1′ connected to the samerotor 110. FIG. 20D in turn discloses a transfer of a first tube fromfirst holder 14 of a fluid processing device 1 to a position outside ofthe centrifuge, e.g. to a holder rack, and from there back to secondholder 22 of the same or a different fluid processing device 1. However,the transfer may also be a transfer from a first, second or third holderposition to a position outside of the centrifuge to, e.g., a wasteposition, in which case there is no transfer back into the centrifuge tothe second holder. The expression “outside of the centrifuge” refers tothe opposite of the expression “within the centrifuge”. It may relate,for example, to a position where the fluid processing device isdisconnected from the rotor, or outside of the centrifuge's protectionshield or the like.

In order to carry out the automatic transfer, merely a gripper isrequired that is capable of engaging and disengaging with the first tubeand that can be freely moved in three dimensions in order to transferthe first tube from a first holding position to a second holdingposition within the centrifuge. Since designing such gripper is withinthe range of what a person skilled in the art does routinely, no furtherdetails on the use and shape of a gripper are given.

Below is an example of a method for processing a fluid using anautomated transfer of a first tube from the first holder to the secondholder for purifying nucleic acids. The method includes the use ofmultiple fluid processing devices 1 that each have a first holder 14, asecond holder 22, a third holder 66, a first container 10 and a thirdcontainer 68. The fluid processing devices are compression-moulded inone piece from polymeric material to be light and rigid to withstandcentrifugal stress. The first holder 14 is form-fit for holding a firsttube 18, e.g. a QIAprep spin column having a filter element 19, e.g. asilica-gel membrane, the second holder 22 is form-fit for holding asecond tube 26, e.g. a collection tube (2 ml), and the third holder 66is empty and used as a third container 68. The tubes are commerciallyavailable from the applicant. Note that the outer cross section of thespin column (first tube 18), which at the position where it is held bythe first holder 14 is 60.8 mm² (8.8 mm diameter) is form-fit to theinner cross section of the collection tube (second tube 26). This makesit possible to insert the spin column into the collection tube in a waythat the collection tube can hold the spin column during centrifugationand that fluid flowing through the spin column flows into the secondcontainer volume 65 of the collection tube. Further, the size of thefirst container volume 12, i.e. the fluid volume that it can hold duringcentrifugation without coming into contact with outlet 52 of the firsttube 18 or without spilling over the rim of the fluid processing deviceis approx. 4 ml, of which typically 2 ml are used.

In a first step, the spin columns (first tubes 18) are inserted into therespective first holder 14 of each fluid processing device 1 and thecollection tubes (second tubes 26) are inserted into the respectivesecond holder 22 of each fluid processing device 1. In a second step,the fluid processing devices 1 are connected to the rotor 110 of acentrifuge by inserting the fluid processing devices 1 into respectiveconnection means 104. The connection means are adapted for holding afluid processing device 1 during centrifugation. At the same time, theconnection means 104 provide for a swinging connection with rotor 110 toallow each fluid processing device 1 to swing outwardly duringcentrifugation.

In a third step, various biological samples, e.g resuspended bacterialcells are lysed and neutralised prior to dispensing into the respectivethird containers 68 of the multiple fluid processing devices within thecentrifuge. Subsequently, the multiple fluid processing devices 1 arecentrifuged at a centrifugal force equivalent to approx. 12000×g untilthe cell debris of the various biological samples have been pelleted.Then, the supernatant fractions of the lysates (first fluid) are eachwithdrawn from respective third containers 68 and dispensed into therespective spin columns (first tubes 18) of the respective fluidprocessing devices 1.

Then, in order to carry out a binding step, the spin columns (firsttubes 18) containing the supernatant fractions are subsequentlycentrifuged at an acceleration of about 12000×g until the clearedlysates have more or less completely passed through the respectivesilica-gel membranes. The fluids that have passed through the silica-gelmembranes (filter elements 19) are collected in respective firstcontainers 10. At this point, due to the binding property of thesilica-gel material to nucleic acid, only the nucleic acids remain withthe respective silica-gel membranes.

After the binding step, one or more washing steps are carried out tofurther purify the nucleic acids bound to the filter elements 19. Thisis done by dispensing a first reagent, e.g. wash buffers PB, PE(available from Qiagen) into the respective spin columns and byafterwards centrifugating the spin columns (12000×.g for about 1 min)until the first reagent and removed nucleic acid contaminants havepassed through the filter elements 19 into the respective firstcontainers 10. This step may be repeated several times with the same ordifferent reagents.

After binding and washing, the respective spin columns (first tubes 18)are automatically withdrawn from respective first holders 14 by agripper and transferred and placed into respective collection tubes(second tubes 26) that are already in place and held by second holders22. As a next step, elution fluid (second fluid), e.g. water or elutionbuffer EB (available from Qiagen) is dispensed into respective spincolumns (first tubes 18). This step is followed by a furthercentrifugation for 1 min at 12000×g until the eluted fluids have passedthrough the silica-gel membranes (filter elements 19) into therespective collection tubes (second tubes 26). During centrifugation,the elution fluids together with the respective purified nucleic acidsare collected in the second tubes 26 of the respective fluid processingdevices 1 and ready for further use. Details of the above process arealso disclosed in the Protocol: Plasmid DNA Purification Using theQIAprep Spin Miniprep Kit and a Microcentrifuge (QIAGEN QIAprep®Miniprep Handbook, Second Edition, June 2005).

1. A fluid processing device for use in a centrifuge having a rotor,said fluid processing device comprising: a) a first holder for holding afirst tube having a first cross section; said first tube having a firstcap; and b) at least one first cap fixture means for holding said firstcap in a defined position with respect to said first holder duringcentrifugation in said centrifuge, wherein the at least one first capfixture means is arranged such that the first cap is held at a positionthat leaves the first tube's inlet opening open.
 2. The fluid processingdevice according to claim 1 comprising a second holder for holding afirst tube.
 3. The fluid processing device according to claim 2 whereinsaid second holder is arranged for holding a second tube.
 4. The fluidprocessing device according to claim 3 whereby said second tube has asecond cross section that is different from said first cross section. 5.The fluid processing device according to claim 3 whereby said secondholder is form-fit to the shape of said second tube for holding saidsecond tube.
 6. The fluid processing device according to claim 3 whereinsaid second tube is a second container.
 7. The fluid processing deviceaccording to claim 6 wherein said second container is shaped for holdingsaid first tube so that a fluid flowing through said first tube flowsinto said second container.
 8. The fluid processing device according toclaim 1 comprising at least one second cap fixture means for holding asecond cap of said second tube during centrifugation.
 9. The fluidprocessing device according to claim 1 whereby at least one of saidfirst cap fixture means and, if present, said second cap fixture meansinclude a cap enclosure structure for partially enclosing respectivefirst cap or second cap during centrifugation.
 10. The fluid processingdevice according to claim 1 whereby at least one of said at least onefirst cap fixture means and, if present, said at least one second capfixture means are integral with respective first holder or secondholder.
 11. The fluid processing device according to claim 1 whereinduring centrifugation, at least one of said first tube and second tubeare exposed to an acceleration of at least 100 g.
 12. The fluidprocessing device according to claim 1 wherein during centrifugation, atleast one of said first tube and second tube are exposed to anacceleration of at least 1000 g
 13. The fluid processing deviceaccording to claim 1 wherein during centrifugation, at least one of saidfirst tube and second tube are exposed to an acceleration of at least10000 g.
 14. The fluid processing device according to claim 1 comprisingconnection means for removably connecting said fluid processing devicewith a rotor of said centrifuge.
 15. The fluid processing deviceaccording to claim 1 wherein said fluid processing device is made of onepiece.
 16. A method for processing a fluid comprising: a) applying acentrifugal force to at least one fluid processing device; each of saidat least one fluid processing devices having a first holder at a firstholding position and a second holder at a second holding position forholding tubes and at least one first cap fixture means, wherein duringthe applying of a centrifugal force, a first tube having a first cap isheld in the first holder and said first cap is held, by the cap fixturemeans, in a defined position with respect to said first holder such thatthe first cap is held at a position that leaves the first tube's inletopening open; and b) automatically transferring a first tube from saidfirst holder of one of said at least one fluid processing devices tosaid second holder of one of said at least one fluid processing devices.